Watch dial with integrally formed raised symbols

ABSTRACT

A watch dial having a dial plate with integrally formed raised symbols, the dial plate having a substantially homogeneously appearing background surface and the raised symbols having a top face and side surfaces which form sharp corners with the top face such that the raised symbols have a substantially different appearance from the dial plate background surface.

United States Patent 1 Richard 1451 Apr. 16, 1974 WATCH DIAL WITHINTEGRALLY FORMED RAISED SYMBOLS Inventor: Pierre Richard, Porrentruy,Switzerland Assignee: Jap, S. A., Bure- Beme,

.wi zsr and Apr, 27, 1971 (Under Rule 47) Appl. No.: 137,990

Related US. Application Data Division of Ser. No. 817,970, April 21,1969.

Filed:

Foreign Application Priority Data Apr. 26, 1968 Switzerland 6236/6811.8. CI. 58/127 R Int. Cl. G04b 19/06 Field of Search 58/127 R; 29/177References Cited UNITED STATES PATENTS Stern 58/127 R X 493,927 3/1893Hess 58/127 R FOREIGN PATENTS OR APPLICATIONS 1,145.809 12/1958 Germany58/127 R 408,791 9/1966 Switzerland 58/127 R Primary Examiner-George H.Miller, Jr.

Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher [57] ABSTRACT Awatch dial having a dial plate with integrally formed raised symbols,the dial plate having a substantially homogeneously appearing backgroundsurface and the raised symbols having a top face and side surfaces whichform sharp corners with the top face such that the raised symbols have asubstantially different appearance from the dial plate backgroundsurface.

1 Claim, 2 Drawing Figures WATCH DIAL WITH INTEGRALLY FORMED RAISEDSYMBOLS cRoss REFERENCE TO RELATED APPLICATION BACKGROUND OF THEINVENTION The invention relates to watch dials with raised symbols thatare formed in one piece out of the dial during fabrication of thelatter,one part of the forming tool having hollows corresponding to the symbolsto be raised.

In some of the known methodsfor making watch dials of this kind, theraised symbols are obtained by stamping a dial blank having a thicknesscorresponding to that of the final dial, the thickness of the stampedblank then being equal to that of the dial. In the case of thin dials,such as watch dials, which commonly have a thickness of 40/100 mm, it isnot easy to stamp symbols in high relief out of the blank. It isnecessary to use extremely powerful presses that are expensive andrapidly wear the tools These drawbacks are of a less serious nature inother known methods using a blank that is much thicker than the finaldial. After stamping, however, the thickness of the blank must bereduced by machining its reverse face, entailing an additional operationthat is laborious and delicate. p

In stillother known methods, the raised symbols are formed using maleand female dies. This operation can be performed using presses lesspowerful than the stamping presses for the previously described knownmethods. To form thesymbols, there is required not onlya female diehaving hollows corresponding to the negative of the symbols that are tobe raised but also a male die incorporating the positive of thesesymbols.

Moreover, the male and female dies must precisely match. Consequently,the tools required forthis kind of stamping are much more expensive thanthose for the kind of stamping previously described.

With these known methods, furthermore, it is not easy toobtain, inasingle forming step, symbols with sharply defined faces meeting alongsharp corners. it margin Another disadvantage of these known methods isthat the dial blank must be formed while still unfinished, because ofthe very great stresses to'which it is subjected during stamping. Oneconsequence of this disadvantage is that the raised symbols are in the,way when later finishing the background of the dial. Since ij isimpossible to work up to the very edges of the symbols when finishingthe dial background, it is useless to employ those finishing operationsintended to give the very finest appearance to the dial background,because an unfinished margi is always left surrounding each symbol.

Another consequence of this disadvantage is that a series of dials thathave been ordered cannot be worked advantages. They obtain the raisedsymbols by partly punching them out of the dial blank. With these knownmethods, however, the height of the symbols is limited by the thicknessof the dial.

j SUMMARY OF THE INVENTION An object ofthe invention is a watch dialwith raised symbolsformed by a method that avoids all of theaforementioned disadvantages.

This and other objects of the invention will be apparent from thefollowing detailed description.

' BRIEF DESCRIPTION OF THE DRAWING The invention will be described, withreference to the Figures of the accompanying drawing, wherein FIG. 1 isa side view partly in section showing the dial blank and the formingtool at one step in the formation of the finished dial of the invention;and

FIG. 2 is a view similar to that of FIG. 1, showing a second step.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the Figures,the forming tool comprises a first part consisting of a die I. The dieembodies in its upper face a bowl-shaped depression 2, the diameter ofwhich is less than that of the dial blank 3, but larger than that of thefinal dial. The die 11 has two blind holes 4 which receive the dial feet5. The diameter of these holes is slightly greater than that of the feetso as to provide a small amount of play withinthe holes. The

holes 4 are deeper than the feet 5 are long. An annular projection 6,triangular in cross section, forms the rim of the depression 2. A flatface '7 surrounds the projec-' tion. The height of the projection 6above the face 7 is less than the thickness of the blank 3. If thelatter has a thickness of 40/100 mm, the height of the projection 6above the face 7 is preferably between 20 and 25/ l 00 The forming toolillustrated comprises a second part consisting of a punch 8, which hasthe same outer diameter as the die face 7. The lower face 9 of the punchis flat, and incorporates hollows 10 constituting the negative of thesymbols that are to be raised in the dial.

In accordance with the method for making the dial of the invention, thefirst stepis to fill the depression 2 and the holes 4 completely with asubstance that forms a cushion 11. The cushion can consist of any liquidor pasty substance, such as water or of an aqueous solution of starch,of oil, or of a heavy grease. A transparent substance is preferablychosen, making the holes 4 visible through the cushion ll.

If the substance used is a liquid, the depression 2 is filled up untilthe cushion ill forms a convex meniscus above the upper edge of theprojection 6, thereby ensuring that the entire central part of thereverse side of the blank 3, extending above the depression 2, is indirect contact with the cushion 111, when the blank is placed on the dieI, as shown in FIG. I. If, on the other hand, the cushion is made of apasty material, care is taken to fill the depression 2 with a sufficientquantity of the material to ensure the same direct contact.

After having filled the depression 2in the manner described, the blank 3is placed in the position seen in FIG. l, the feet 5 being introducedinto the die holes 4. Since the depression 2 is brimming over with theliquid or pasty substance, the blank does not immediately fall to theposition shown in FIG. ll; instead, it floats on the cushion 111, abovethe annular projection 6. If the blank is slightly pressed on, theexcess amount of substance in the depression 2 flows over the projection6 until the blank rests on the latter, as seen in FIG. 1, in

which the dial blank is in position for forming.

The forming is done by forcibly and abruptly lowering the punch 8against the blank until there is reached the position seen in FIG. 2. Assoon as the punch face 9 contacts the obverse of the blank, the pressureon the latter causes the projection 6 to penetrate into the reverse ofthe blank. At the same time, the cushion 11 is subjected to tremendouspressure, since the central part of the blank is forced within thedepression 2, as seen in FIG. 2. Inasmuch as the liquid or pastysubstance of the cushion 11 is incompressible and, moreover, as theprojection 6 holds the substance within the depression, the pressure ofthe blank on the cushion 11 is spread over the entire area of thelatter, causing those parts of the blank located opposite the punchhol-.

lows 10 to enter the latter and-to form the raised symbols 12. Sinceboth liquids and pasty substances easily take on the shape of thecontainer holding them, the portions 11a of the cushion 11 enter thepunch hollows 10, forcing the material of the blank 3 into intimatecontact with the sides and bottoms of the hollows 10.

The forming operation described can be carried out using a smallfriction fly-press developing a maximum of thirty or so tons pressure.At the end of the operation, the punch 8 compresses on the die face 7the blank edge 13 located outside of the projection 6, as seen in FIG.2.

Since the volume occupied by the blank 3 in the depression 2 issubstantially greater than the sum of the volumes of the cushionportions 11a forced into the punch hollows 10, it is essential that theprojection 6 does not constitute a perfectly sealed joint. It mustpermit the liquid or paste of the cushion 11 to escape between the blankand the projection 6, when the blank has already been raised against thebottom of the hollows 10 while the punch 8 continues to descend.Otherwise the joint constituted by the projection 6 should not pennitthe liquid or the paste of the cushion 11 to escape until the symbolsare completely formed. If necessary, the effectiveness of this joint canbe improved by tiny projections or grooves (not shown) incorporated inthe punch face 9 opposite the projection 6. To the same end, a secondprojection (not shown), concentric to the projection 6, can be providedin the die face 7.

Tests employing the method described have shown that the raised symbolshave perfectly fiat side and upper faces meeting in sharp and very welldefined corners. The symbol 12 shown in the drawing is constituted by abar. The method can be used. however, to form in the blank 3 raisedsymbols of any desired shape in planview. These symbols can be Arabicnumerals or a trademark consisting of letters or of a design.

When using the method described above, it is not at all necessary thatthe feet 5 are previously fixed to the blank; instead, they can be fixedafter the forming. As illustrated in FIG. 2, the raised symbols can beformed in any area of the dial and completely independently of theposition occupied by the feet 5. In the example shown, the foot 5 comesto be positioned within the symbol 12. Tests undertaken with the footcoming to be positioned on the sides 14 of the symbol 12 (the foothaving been soldered to the blank before forming) demonstrate that thislocation is not disadvantageous; the solder connection of the foot tothe side 14 holds perfectly, and the foot remains held to the side withall of the tightness desired. A play of a few hundredths of a millimeterof the feet 5 in their holes 4 is sufficient to ensure that the pressurecaused by part of the blank 3 forced into the depression 2 istransmitted to the liquid or paste at the bottom of these holes.

In principle, the method described can be used at any stage during themanufacture of the dial. In particular,

, it is altogether possible to carry out all of the finishing operationson the obverse 15 of the blank. The finest surface finish is not harmedby the forming operation. The manufacturer is therefore free to preparea number of blanks beforehand, and to finish the obverses 15 of theseblanks while preparing the forming tools, particularly the punch 8,which is the part of the forming tool requiring the most time to be madeready.

It will be noticed that the openings embodied in the blank 3 for thehands do not prevent use of the described method. While forming, theseopenings are actually closed by the punch face 9. It is only necessaryto prevent droplets of the substance constituting the cushion 11 formpassing through these openings and onto the obverse 15 of the blank,when the latter is placed on the die 1. For this purpose, the openingscan be covered with adhesive paper.

If the dial is intended for a calendar-watch having a date aperture thatis to be surrounded by a dial raised frame, the forming can be done bythe method described, the date aperture being cut out only after theforming is completed.

The raised symbols of the invention can be faceted, of course, after theforming.

After the finishing operations on the dial obverse 15, where these aredone before the forming, the finished face of the blank 3 can be coveredwith a protective coat of lacquer of the sort regularly used in themanufacture of dials. Tests have shown that the described forming methoddoes not damage this coating, and after forming the coating was removedfrom only those areas of the symbols that were to be faceted. Theseuncovered areas can be colored as desired, with a view to obtaining thewanted contrast with the dial background.

In order to apply to the sides 14 of the symbols 12 a color differentfrom that of the dial background, the obverse 15 of the blank must becovered with a protective coating that is destroyed in those areas wherethe symbols are raised out of the surface of the blank. To this end,adhesive paper or a hard lacquer can be applied to the blank.

After forming, the blank is easily taken up by a suction gripper for thepurpose of removing the edge of the blank by turning on a lathe, forexample, and to give the dial its final diameter. During this operationthe dial can also be cambered.

The dial of the invention has the appearance of a dial with appliedsymbols, but at a much lower cost price.

Although the preferred embodiment of the invention has been described,the scope of, and the breadth of protection afforded to, the inventionare limited solely by the appended claims.

What is claimed is:

l. A watch dial comprising a dial plate and raised symbols integrallyformed in said dial plate; said raised symbols having side surfaces anda top face, said side surfaces forming sharp comers with said top face;said dial plate having a background surface wherein said backgroundsurface has a sub-stantially homogeneous appearance; said side surfacesand said top face of said raised symbols having the same appearance,which is substantially different from that of said dial plate backgroundsurface.

1. A watch dial comprising a dial plate and raised symbols integrallyformed in said dial plate; said raised symbols having side surfaces anda top face, said side surfaces forming sharp corners with said top face;said dial plate having a background surface wherein said backgroundsurface has a sub-stantially homogeneous appearance; said side surfacesand said top face of said raised symbols having the same appearance,which is substantially different from that of said dial plate backgroundsurface.